dont bother putting anythign into tradeskills till at least level 100 and put just enough into pistol/fling/MR to get some intel pistols on (dont forget the various buffs )
the engi pistol is not a bad pistol damage-wise against aliens and RK mobs, but it's crap against SL mobs. the only thing i would do is gather the parts needed to make it to change up your gameplay a little (notum fragment, the brain thing from bucketheads and technoscavengers for example).
Greetings,
Ellarisa